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www.clim-past-discuss.net/6/1701/2010/
doi:10.5194/cpd-6-1701-2010
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under the Creative Commons Attribution 3.0 License.
Southern Ocean warming and hydrological change during the Paleocene–Eocene thermal maximum
1Biomarine Sciences, Institute of Environmental Biology, Utrecht University, Laboratory of Palaeobotany and Palynology, Budapestlaan 4, 3584 CD Utrecht, The Netherlands
2Royal Netherlands Institute for Sea Research (NIOZ), Department of Marine Organic Biogeochemistry, P.O. Box 59, 1790 AB, Den Burg, Texel, The Netherlands
3Marum – Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, 28359 Bremen, Germany
4Department of Earth Sciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, The Netherlands
Abstract. A brief (~150 kyr) period of widespread global average surface warming marks the transition between the Paleocene and Eocene epochs, ~56 million years ago. This so-called ''Paleocene–Eocene thermal maximum'' (PETM) is associated with the massive injection of 13C-depleted CO2 and/or CH4, reflected in a negative carbon isotope excursion (CIE). Biotic responses include a global dominance (acme) of the subtropical dinoflagellate Apectodinium. Here we identify the PETM in a marine sedimentary sequence deposited on the East Tasman Plateau at Ocean Drilling Program (ODP) Site 1172 and show that Southwest Pacific sea surface temperatures increased from ~26 °C to ~33 °C during the PETM. Such temperatures before, during and after the PETM are >10 °C warmer than predicted by paleoclimate model simulations for this latitude, suggesting that not only Arctic, but also Antarctic temperatures are underestimated in simulations of ancient greenhouse climates by current generation fully-coupled climate models. An early influx of abundant Apectodinium confirms that environmental change preceded the CIE on a global scale. Organic dinoflagellate cyst assemblages suggest a local decrease in the amount of river run off reaching the core site during the PETM, possibly in concert with eustatic rise. Moreover, the assemblages suggest changes in seasonality of the regional hydrological system and storm activity. Finally, significant variation in dinoflagellate cyst assemblages during the PETM indicates that the Southwest Pacific climate state was more dynamic during this event than before and after, a finding comparable to similar studies of PETM successions from the New Jersey Shelf.
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Notice on Discussion StatusCitation: Sluijs, A., Bijl, P. K., Schouten, S., Röhl, U., Reichart, G.-J., and Brinkhuis, H.: Southern Ocean warming and hydrological change during the Paleocene–Eocene thermal maximum, Clim. Past Discuss., 6, 1701-1731, doi:10.5194/cpd-6-1701-2010, 2010. Bibtex EndNote Reference Manager XML
